Liquid crystal display module comprising a polarizer having a plurality of conductive layers and having a touch sensing capability

ABSTRACT

A liquid crystal display module includes a liquid crystal module and a polarizer on the liquid crystal module. The liquid crystal module includes an upper substrate, an upper electrode layer, a first alignment, a liquid crystal layer, a second alignment layer, a thin film transistor panel, and a lower polarizing layer. The polarizer includes a first transparent conductive layer, an upper polarizing layer, and a second transparent conductive layer on the second surface of the upper polarizing layer. A number of first electrodes are electrically connected with the first transparent conducive layer, a number of second electrodes are electrically connected with the second transparent conducive layer. The first transparent conductive layer includes a number of carbon nanotubes substantially aligned along a second direction, and the second transparent conductive layer includes a number of carbon nanotubes substantially aligned along a first direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims all benefits accruing under 35 U.S.C. §119 fromChina Patent Application No. 201210255728.X, filed on Jul. 23, 2012, inthe China Intellectual Property Office, the disclosure of which isincorporated herein by reference. The application is also related tocopending application entitled, “LIQUID CRYSTAL DISPLAY MODULE”, filedMar. 15 2015. U.S Ser. No. 13/837,359.

BACKGROUND

1. Technical Field

The present disclosure relates to liquid crystal display module,particularly to a liquid crystal display module with touch sensingcapability.

2. Description of Related Art

A conventional liquid crystal display module for a liquid crystaldisplay (LCD), according to the prior art, generally includes a firstpolarizer, a thin film transistor panel, a first alignment layer, aliquid crystal layer, a second alignment layer, a common electrode layer(e.g., an indium tin oxide (ITO) layer), an upper board, and a secondpolarizer. The TFT panel includes a plurality of pixel electrodes. Thepolarizing directions of the first and second polarizer areperpendicular to each other. When a voltage is applied between the pixelelectrode and the common electrode layer, the liquid crystal moleculesin the liquid crystal layer between the first alignment layer and thesecond alignment layer align along a same direction to make the lightbeams polarized by the first polarizer irradiate on the second polarizerdirectly without rotation. The polarized light beams cannot pass throughthe first polarizer. Without a voltage applied to the pixel electrodeand the common electrode layer, the polarized light beams rotated by theliquid crystal molecules can pass through the second polarizer.Selectively applying voltages between different pixel electrodes and thecommon electrode layer can control the on and off of different pixels,thus displaying images.

A conventional polarizing layer is made by using a transparent polymerfilm (e.g., PVA film) to absorb the dichroism material, and thedichroism material. The dichroism material is infiltrated into thetransparent polymer film, and the transparent polymer film align withthe dichroism material in one direction. In addition to the polarizinglayer, the conventional polarizer also includes protective layers,adhesive layer, separating layer covered on two opposite surfaces of thepolarizing layer. During the manufacturing of the liquid crystal displayscreen, the second polarizer is directly attached to a top surface ofthe upper board.

In recent years, there is continuous growth in the number of electronicapparatuses equipped with optically transparent touch panels in front oftheir respective display devices (e.g., liquid crystal display screen).The touch panel is commonly attached to the top surface of the secondpolarizer. However, this arrangement will increase a thickness of theelectronic apparatuses. Further, the touch panel and the secondpolarizer are individually manufactured and assembled, which increasesthe complexity of the manufacturing process, and increases the cost forproduction.

What is needed, therefore, is to provide a LCD module for solving theproblem discussed above.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the embodiments can be better understood with referenceto the following drawings. The components in the drawings are notnecessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the embodiments. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is a schematic cross-sectional view of an embodiment of a LCDmodule.

FIG. 2 is a schematic view of an embodiment of a polarizer in the LCDmodule of FIG. 1.

FIG. 3 shows a scanning electron microscope image of a carbon nanotubedrawn film.

FIG. 4 is a schematic view of a carbon nanotube segment.

FIG. 5 is a schematic cross-sectional view of one embodiment of a LCDmodule.

FIG. 6 is a top view of one embodiment of a second transparentconductive layer in the LCD module of FIG. 5.

FIG. 7A shows a touch point locating system of one embodiment of the LCDmodule.

FIG. 7B shows a schematic view of a combination of a first transparentconductive layer and a second transparent conductive layer of FIG. 7A.

FIG. 8A shows a flowchart of a method for locating a touch point on theLCD module.

FIG. 8B shows a flowchart of a method for determining a coordinate ofthe touch point on the system shown in FIG. 7B.

FIG. 9A shows signal waveforms of sensed electrical signals by anysensing electrode shown in FIG. 7B during touching.

FIG. 9B shows an enlarged view of waveform of an electrical signal readout by a sensing electrode corresponding to a pulse signal input by aspecific driving electrode when no touch point is present on the systemshown in FIG. 7B.

FIG. 9C shows a comparison of an enlarged view of waveform of anelectrical signal read out by a sensing electrode corresponding to apulse signal input by a specific electrode when a touch point is presenton the system shown in FIG. 7B with the enlarged view of the waveformshown in FIG. 9B.

FIG. 10A shows a touch point locating system of another embodiment ofthe LCD module.

FIG. 10B shows a schematic view of a combination of a first transparentconductive layer and a second transparent conductive layer of FIG. 10A.

FIG. 11 shows a flowchart of a method for determining a coordinate of atouch point on the system shown in FIG. 10B.

FIG. 12A shows the signal waveforms of the sensed electrical signals byany sensing electrode shown in FIG. 10B during touching.

FIG. 12B shows an enlarged view of waveform of an electrical signal readout by a sensing electrode corresponding to a pulse signal input by aspecific driving electrode when no touch point is present on the systemshown in FIG. 10B.

FIG. 12C shows a comparison of an enlarged view of waveform of anelectronic signal read out by a sensing electrode corresponding to apulse signal input by a specific driving electrode when a touch point ispresent on the system shown in FIG. 10B with the enlarged view of thewaveform shown in FIG. 12B.

FIG. 13A shows a flowchart of another embodiment of a method fordetermining the coordinate of the touch point in the system shown inFIG. 10B.

FIG. 13B shows a plurality of touch points selected along x-axiscorresponding to the driving electrode designated as “13.”

DETAILED DESCRIPTION

The disclosure is illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings in which likereferences indicate similar elements. It should be noted that referencesto “an” or “one” embodiment in this disclosure are not necessarily tothe same embodiment, and such references mean at least one.

Referring to FIG. 1 and FIG. 2, one embodiment of a liquid crystaldisplay (LCD) module 10 includes a polarizer 11 and a liquid crystalmodule 12. The polarizer 11 is capable of sensing touches, occurredthereon, and polarizing light.

The polarizer 11 includes a first transparent conductive layer 102, anupper polarizing layer 114, and a second transparent conductive layer104. The polarizer 11 is stacked on the liquid crystal module 12. Theupper polarizing layer 114 is sandwiched between the first transparentconductive layer 102 and the second transparent conductive layer 104.The polarizer 11 further includes a plurality of first electrodes 106and a plurality of second electrodes 108. The plurality of firstelectrodes 106 are spaced from each other and electrically connected tothe first transparent conductive layer 102. The plurality of secondelectrodes 108 are spaced with each other and electrically connected tothe second transparent conductive layer 104. The polarizer 11 issuitable for a touch sensing type LCD screen.

The upper polarizing layer 114 can be an insulating material layerhaving a light polarizing function. Specifically, the upper polarizinglayer 114 includes a transparent polymer film (e.g., PVA film) and adichroism material infiltrated in the transparent polymer film. Thedichroism material can be iodoquinine sulfate. The molecules of thedichroism material can align along the same direction.

The polarizing layer 114 includes a first surface away from the liquidcrystal module 12, and a second surface adjacent to the liquid crystalmodule 12. The first transparent conductive layer 102 can be directly incontact with the first surface of the polarizing layer 114. The firsttransparent conductive layer 102 can be an anisotropic impedance layer.In the present disclosure, the anisotropic impedance means a structurehaving a relatively low impedance direction D and a relatively highimpedance direction H on the same surface (e.g., the surface of thefirst transparent conductive layer 102). The electrical conductivity ofthe anisotropic impedance layer on the relatively high impedancedirection H is smaller than the electrical conductivities of theanisotropic impedance layer on other directions. The electricalconductivity of the anisotropic impedance layer on the relatively lowimpedance direction D is larger than the electrical conductivities ofthe anisotropic impedance layer in other directions. The relatively highimpedance direction H is different from the relatively low impedancedirection D. In one embodiment, the relatively high impedance directionH is perpendicular to the relatively low impedance direction D. Therelatively high impedance direction H and the relatively low impedancedirection D of the anisotropic impedance layer can be achieved by havinga plurality of conductive belts having a low conductivity aligned alongthe relatively high impedance direction H and a plurality of conductivebelts having a high conductivity aligned along the relatively lowimpedance direction D, and the plurality of conductive belts having thelow conductivity and the plurality of conductive belts having the lowconductivity are electrically connected with each other. In anotherembodiment, the relatively high impedance direction H and the relativelylow impedance direction D of the anisotropic impedance layer can beachieved by having a carbon nanotube film comprising orderly arrangedcarbon nanotubes. The first transparent conductive layer 102 can have asquare shape having two sides perpendicular to the relatively highimpedance direction H and two sides perpendicular to the relatively lowimpedance direction D. The relative low impedance direction D can bedefined as a second direction, such as a Y direction shown in FIG. 2.The relative high impedance direction H can be defined as a firstdirection, such as an X direction shown in FIG. 2. The first directioncan be perpendicular with the second direction.

The plurality of first electrodes 106 is spaced with each other andarranged in a row along the first direction. More specifically, theplurality of first electrodes 106 are arranged on a side of the firsttransparent conductive layer 102. A length along the first direction ofeach first electrode 106 can be between about 1 mm to about 8 mm. Adistance between the two adjacent first electrodes 106 can be betweenabout 3 mm to about 5 mm. A signal input by each first electrode 106 tothe first transparent conductive layer 102, or received from the firsttransparent conductive layer 102, will transmit mostly along the Ydirection. The directional characteristic of the signal transmittance inthe first transparent conductive layer 102 can be used as a determiningbasis for the polarizer 11 to determine a touch location. It is to beunderstood that the size and pitch of the plurality of first electrodes106 can change depending on the desired resolution and application. Theplurality of first electrodes 106 can be located on the surface of thefirst transparent conductive layer 102, near the side. The firstelectrodes 106 can be formed by screen printing, sputtering,evaporating, or coating methods.

The second transparent conductive layer 104 can be directly in contactwith the second surface of the upper polarizing layer 114. The secondtransparent conductive layer 104 can also be the anisotropic impedancelayer. The relatively high impedance direction H of the secondtransparent layer 104 is along the Y direction, and the relatively lowimpedance direction D of the second transparent layer 104 is along the Xdirection. The second electrodes 108 are electrically connected with thesecond transparent conductive layer 104. The second electrodes 108 canbe disposed on one side of the second transparent conductive layer 104at unequal intervals. The second electrodes 108 can be formed in a rowextending along the Y direction. The first transparent conductive layer102 overlaps the second transparent conductive layer 104 in a thirddirection (i.e., a Z direction shown in FIG. 2), defined from the firsttransparent conductive layer 102 to the second transparent conductivelayer 104. The third direction can be substantially perpendicular to thefirst direction and the second direction. A touch region 150 is formedat the overlapped portions between the first transparent conductivelayer 102 and the second transparent conductive layer 104.

In some embodiments, the first transparent conductive layer 102 includesa first carbon nanotube layer, and the second transparent conductivelayer 104 includes a second carbon nanotube layer. Both the first carbonnanotube layer and the second carbon nanotube layer include a carbonnanotube film having anisotropic electrical conductivity. Carbonnanotubes of the first carbon nanotube layer can be substantiallyarranged along the second direction, so that the first carbon nanotubelayer has a larger electrical conductivity at the second direction thanat other directions. Carbon nanotubes of the second carbon nanotubelayer can be substantially arranged along the first direction, so thatthe second carbon nanotube layer has a larger electrical conductivity atthe first direction than at other directions.

In some embodiments, both the first carbon nanotube layer and the secondcarbon nanotube layer comprise a plurality of carbon nanotubes. In someembodiments, each of the first carbon nanotube layer and the secondcarbon nanotube layer can be or include at least one carbon nanotubedrawn film.

The carbon nanotube drawn film includes a plurality of carbon nanotubesthat can be arranged substantially parallel to a surface of the carbonnanotube drawn film. A large number of the carbon nanotubes in thecarbon nanotube drawn film can be oriented along a preferredorientation, meaning that a large number of the carbon nanotubes in thecarbon nanotube drawn film are arranged substantially along the samedirection. An end of one carbon nanotube is joined to another end of anadjacent carbon nanotube arranged substantially along the samedirection, by Van der Waals attractive force. A small number of thecarbon nanotubes may be randomly arranged in the carbon nanotube drawnfilm, and has a small if not negligible effect on the larger number ofthe carbon nanotubes in the carbon nanotube drawn film arrangedsubstantially along the same direction. The carbon nanotube drawn filmis capable of forming a free-standing structure. The term “free-standingstructure” can be defined as a structure that does not have to besupported by a substrate. For example, a free standing structure cansustain the weight of itself when it is hoisted by a portion thereofwithout any significant damage to its structural integrity. So, if thecarbon nanotube drawn film is placed between two separate supporters, aportion of the carbon nanotube drawn film, not in contact with the twosupporters, would be suspended between the two supporters and yetmaintain film structural integrity. The free-standing structure of thecarbon nanotube drawn film is realized by the successive carbonnanotubes joined end to end by Van der Waals attractive force.

It can be appreciated that some variation can occur in the orientationof the carbon nanotubes in the carbon nanotube drawn film as can be seenin FIG. 3. Microscopically, the carbon nanotubes oriented substantiallyalong the same direction may not be perfectly aligned in a straightline, and some curved portions may exist. It can be understood that somecarbon nanotubes located substantially side by side and oriented alongthe same direction being contact with each other cannot be excluded.

More specifically, referring to FIG. 4, the carbon nanotube drawn filmincludes a plurality of successively oriented carbon nanotube segments143 joined end-to-end by Van der Waals attractive force therebetween.Each carbon nanotube segment 143 includes a plurality of carbonnanotubes 145 substantially parallel to each other, and joined by Vander Waals attractive force therebetween. The carbon nanotube segments143 can vary in width, thickness, uniformity, and shape. The carbonnanotubes 145 in the carbon nanotube drawn film are also substantiallyoriented along a preferred orientation.

In one embodiment, the carbon nanotube drawn film can be drawn out froman array of carbon nanotubes. The carbon nanotube drawn film can beformed by selecting one or more carbon nanotubes having a predeterminedwidth from the array of carbon nanotubes, and pulling the carbonnanotubes at a roughly uniform speed to form carbon nanotube segmentsthat are joined end to end to achieve a uniform carbon nanotube drawnfilm.

The carbon nanotube segments can be selected by using a tool, such asadhesive tape, pliers, tweezers, or other tools allowing multiple carbonnanotubes to be gripped and pulled simultaneously to contact with thearray of carbon nanotubes. Referring to FIG. 4, each carbon nanotubesegment 143 includes a plurality of carbon nanotubes 145 substantiallyparallel to each other, and combined by Van der Waals attractive forcetherebetween. The pulling direction can be substantially perpendicularto the growing direction of the array of carbon nanotubes.

The drawn carbon nanotube film has the smallest resistance at thepulling direction, and the largest resistance at a directionsubstantially perpendicular to the pulling direction.

In one embodiment, both of the first carbon nanotube layer and thesecond carbon nanotube layer include a number of carbon nanotube drawnfilms located side by side or stacked with each other. Carbon nanotubesof the first carbon nanotube layer are arranged substantially along thesecond direction Y. Carbon nanotubes of the second carbon nanotube layerare arranged substantially along the first direction X. The length andwidth of the carbon nanotube drawn films are not limited, because thecarbon nanotube drawn films can be located side by side or stacked witheach other in the first carbon nanotube layer and the second carbonnanotube layer. In one embodiment, each carbon nanotube drawn film has alight transmittance greater than 85%, and the number of layers of thecarbon nanotube drawn films is not limited, so long as the first carbonnanotube layer and the second carbon nanotube layer have proper lighttransmittance.

In some embodiments, each of the first carbon nanotube layer and thesecond carbon nanotube layer includes a carbon nanotube composite film.The carbon nanotube composite film includes a carbon nanotube drawn filmand polymer materials infiltrating the carbon nanotube drawn film.Spaces can exist between adjacent carbon nanotubes in the carbonnanotube drawn film, and thus the carbon nanotube drawn film includes anumber of micropores defined by the adjacent carbon nanotubes therein.The polymer material is filled into the micropores of the carbonnanotube drawn film to form the carbon nanotube composite film. Thepolymer materials can be distributed uniformly in the carbon nanotubecomposite film. The carbon nanotube composite film can include one ormore carbon nanotube drawn films. The carbon nanotube composite film canhave a uniform thickness. A thickness of the carbon nanotube compositefilm is only limited by the degree of transparency desired. In oneembodiment, the thickness of the carbon nanotube composite film canrange from about 0.5 nanometers to about 100 microns. The polymermaterial can be transparent, and not limited to a specific material. Thepolymer material can be polystyrene, polyethylene, polycarbonate,polymethyl methacrylate (PMMA), polycarbonate (PC), polyethyleneterephthalate (PET), benzocyclobutene (BCB), or polyalkenamer. In oneembodiment, the polymer material is PMMA.

In some embodiments, each of the first carbon nanotube layer and thesecond carbon nanotube layer includes at least one etched orlaser-treated carbon nanotube drawn film. The etched or laser-treatedcarbon nanotube drawn film has an enhanced anisotropic electricalconductivity. For example, a number of cutting lines along the preferredorientation of the carbon nanotubes can be formed in the first carbonnanotube layer along the second direction through laser or etching.

The first electrodes 106 and the second electrodes 108 can includeconductive materials, such as metals, conductive polymer materials, orcarbon nanotubes. The metals can be gold, silver, copper or any othermetal having a good conductivity. The conductive polymer materials canbe polyacetylene, polyparaphenylene, polyaniline, or polythiophene. Inone embodiment, the first electrodes 106 and the second electrodes 108can be made of conductive silver pastes.

Because both of the first transparent conductive layer 102 and thesecond transparent conductive layer 104 have good anisotropic electricalconductivity, the first transparent conductive layer 102 can be seen asan equivalent of a number of conductive bands, each of which contactingone of the first electrodes 106. Similarly, the second transparentconductive layer 104 can also be seen as an equivalent of a number ofconductive bands, each of which contacting one of the second electrodes108. The conductive bands of the first transparent conductive layer 102are substantially perpendicular to the conductive bands of the secondtransparent conductive layer 104. Thus, a number of capacitances areformed at the intersections of the conductive bands of the firsttransparent conductive layer 102 and the second transparent conductivelayer 104. In operation of the LCD module, one or more contacts can bemade with the polarizer 11 from one or more contact tools (not shown),such as fingers or a stylus. Capacitances of the contact points willchange and can be detected by external circuits connected with the firstelectrodes 106 and the second electrodes 108. The coordinates of thecontact points on the polarizer can be obtained.

The liquid crystal module 12 is located under the second transparentconductive layer 104 of the polarizer 11. The liquid crystal module 12includes an upper substrate 110, an upper electrode layer 116, a firstalignment layer 112, a liquid crystal layer 130, a second alignmentlayer 122, a thin film transistor panel 120, and a lower polarizinglayer 124 stacked together in that order. The upper polarizing layer 114and the lower polarizing layer 124 act together to control the lightextraction intensity.

The upper substrate 110 can be a transparent plate. The upper substrate110 can be made of glass, quartz, diamond, plastic or resin. Thethickness of the upper substrate 110 can range from about 1 millimeterto about 1 centimeter. In one embodiment, the upper substrate 110 is aPET film and the thickness of the upper substrate 110 is about 2millimeters.

The upper electrode layer 116 can include conductive materials, such asmetals, ITO, ATO (tin antimony oxide), conductive polymer materials, orcarbon nanotubes. The metals can be gold, silver, copper or any othermetal having a good conductivity. The conductive polymer materials canbe polyacetylene, polyparaphenylene, polyaniline, or polythiophene. Insome embodiments, the upper electrode layer 116 can be a carbon nanotubefilm. The carbon nanotube film can include a plurality of carbonnanotubes. In one embodiment, the carbon nanotubes of the carbonnanotube film can be disorderly arranged. In one embodiment, the carbonnanotubes of the carbon nanotube film can be orderly arranged.

The first alignment layer 112 can include a number of substantiallyparallel first grooves (not shown) formed thereon. The first grooves arelocated on a lower surface of the first alignment layer 112 opposing theliquid crystal layer 130. The first grooves are used to make the liquidcrystal molecules align along a same direction. The second alignmentlayer 122 can include a number of substantially parallel second grooves(not shown) formed thereon. The second grooves are located on an uppersurface of the second alignment layer 122 opposing the liquid crystallayer 130.

An alignment direction of the first grooves is substantiallyperpendicular to an alignment direction of the second grooves. Thesecond grooves are used to make the liquid crystal molecules alignsubstantially along a same direction. Because the alignment direction ofthe first grooves is substantially perpendicular to the alignmentdirection of the second grooves, the alignment direction of the liquidcrystal molecules differ by about 90 degrees between the first alignmentlayer 112 and the second alignment layer 122, which play a role inshifting the light beams by 90 degrees.

The material of the first alignment layer 112 and the second alignmentlayer 122 can be polystyrenes and derivatives of the polystyrenes,polyimides, polyvinyl alcohols, polyesters, epoxy resins, polyurethanes,or other polysilanes. The first grooves and the second grooves can beformed by a rubbing method, a tilt deposition method, a micro-groovestreatment method, or a SiOx-depositing method. In one embodiment, amaterial of the first alignment layer 112 and the second alignment layer122 is polyimide and a thickness thereof ranges from about 1 micrometerto about 50 micrometers.

The liquid crystal layer 130 includes a number of oval shaped liquidcrystal molecules. Understandably, the liquid crystal layer 130 can alsobe made of other conventional suitable materials, such as alkyl benzoicacid, alkyl cyclohexyl acid, alkyl cyclohexyl-phenol, and phenylcyclohexane. A thickness of the liquid crystal layer 130 ranges fromabout 1 micrometer to about 50 micrometers. In one embodiment, athickness of the liquid crystal layer 130 is about 5 micrometers.

The detailed structure of the thin film transistor panel 120 is notshown in FIG. 1. It is to be understood that the thin film transistorpanel 120 can further include a transparent base, a number of thin filmtransistors located on the transparent base, a number of pixelelectrodes, and a display driver circuit (not shown). The thin filmtransistors correspond to the pixel electrodes in a one-to-one manner.The thin film transistors are connected to the display driver circuit bythe source lines and gate lines. The pixel electrodes are controlled tocooperate with the second transparent conductive layer 104, to apply avoltage to the liquid crystal layer 130. The pixel electrodes correspondto the touch region 150.

The upper polarizing layer 114 functions as an insulating layer in thepolarizer 11 to insulate the first transparent conductive layer 102 andthe second transparent conductive layer 104. Furthermore, the upperpolarizing layer 114 can also cooperate with the lower polarizing layer124 to control the light extraction intensity of the liquid crystalmodule 12. Thus the LCD module 10 can have a low thickness, simplestructure, and low cost.

Referring to FIG. 5 and FIG. 6, another embodiment of a LCD module 20includes a polarizer 11 and a liquid crystal module 12. The polarizer 11is capable of sensing touches occurred thereon and polarizing lights.The polarizer 11 includes a first transparent conductive layer 102, atransparent base 140, an upper polarizing layer 114, and a secondtransparent conductive layer 104 stacked on the liquid crystal module12. The upper polarizing layer 114 is sandwiched between the transparentbase 140 and the second transparent conductive layer 104. The polarizer11 further includes a plurality of first electrodes 106 and a pluralityof second electrodes 108. The plurality of first electrodes 106 arespaced with each other and electrically connected to the firsttransparent conductive layer 102. The plurality of second electrodes 108are spaced with each other and electrically connected to the secondtransparent conductive layer 104. The polarizer 11 is suitable for atouch sensing type LCD screen.

The structure of the LCD module 20 is similar to the structure of LCDmodule 10, except that the LCD module 20 further includes a transparentbase 140, and the first transparent conductive layer 102 is sandwichedbetween the transparent base 140 and the upper polarizing layer 114. Thefirst transparent conductive layer 102 can be a patterned metal oxidelayer formed on the transparent base 140. The patterned metal oxidelayer includes a plurality of transparent conductive belts 118, and eachof the plurality of the transparent conductive belts 118 is electricallyconnected to one of the plurality of the first electrodes 106,respectively.

A material of the transparent conductive belt 118 can be ITO or tinantimony oxide. In one embodiment, the material of the transparentconductive belt 118 is ITO. The transparent conductive belts 118 can beformed by depositing the metal oxide layer on the transparent base 140.The polarizer 11 can be formed by covering the transparent base 140,having the transparent conductive belt 118 thereon, to the upperpolarizing layer 114. The polarizer 11 can be directly located on theliquid crystal module 12. Furthermore, the plurality of transparentconductive belts 118 can be parallel with and spaced from each otherextending along the second direction. The plurality of transparentconductive belts 118 forms a conductive route only along the seconddirection. A width of the transparent conductive belt 118 and a distancebetween adjacent two transparent conductive belts 118 can be changeddepending on the desired resolution. In one embodiment, the distancebetween adjacent two transparent conductive belts 118 ranges from about10 micrometers to about 500 micrometers. The width of the transparentconductive belt 118 ranges from about 10 micrometers to about 5millimeters.

The second transparent conductive layer 104 still includes the carbonnanotube layer, including the plurality of carbon nanotubessubstantially arranged along the second direction. Furthermore, thepolarization of the upper polarizing layer 114 can be parallel with thesecond direction. The second carbon nanotube layer in the secondtransparent conductive layer 104 is the free-standing structure, and thesecond carbon nanotube layer can be formed first and directly attachedon a surface of the upper polarizing layer 114. Thus the secondtransparent conductive layer 104 can be easily integrated into the upperpolarizing layer 114. By comparison, the traditional ITO layer need tobe formed on the polarizing layer via a sputtering method or vacuumevaporation process, however surface of the polarizing layer isdifficult to satisfy the requirement of the sputtering method and thevacuum evaporation process. Therefore, the traditional ITO layer isdifficult to be integrated into the polarizing layer.

In another embodiment, the structures of the first and secondtransparent conductive layers 102, 104 can be exchanged. That is, thefirst transparent conductive layer 102 can be a layer having anisotropicimpedance property, such as the carbon nanotube drawn film, and thesecond transparent conductive layer 104 includes the plurality oftransparent conductive belts 118. Furthermore, the plurality oftransparent conductive belts 118 of the second transparent conductivelayer 104 can be directly deposited on the upper substrate 110 of theliquid crystal module 12.

Referring to FIG. 7A, FIG. 7A shows a touch point locating system of theLCD module of the first embodiment of the present disclosure. Eachsecond electrode 108 connects to an electrical signal input circuit or adriving circuit 17 via a conductive line. The driving circuit 17 inputsdriving electrical signals with the same pulse waveform or otherwaveforms to each second electrode 108 in sequence or simultaneously.Each first electrode 106 connects to an electrical signal readoutcircuit or a sensing circuit 18 via a conductive line to read out sensedelectrical signals of each first electrode 106. The second electrode 108is used as the driving electronic signal pad, while the first electrode106 is used as the sensing electronic signal pad. The driving circuit 17and the sensing circuit 18 are controlled by a controller 19.

FIG. 7B shows a schematic view of the combination of the firsttransparent conductive layer 102 and the second transparent conductivelayer 104. In FIG. 7A and FIG. 7B, ten second electrodes 108 are shownand designated as 3, 8, 13, 18, 23, 28, 33, 38, 43, and 48, and thirteenfirst electrodes 106 are shown and designated as 3, 8, 13, 18, 23, 28,33, 38, 43, 48, 53, 58 and 63. When the stylus or the finger touches theLCD module, the capacitance value C generated by the touch gives thesensed electrical signals of the first electrodes 106 unique features,so the coordinate of the touch point such as x coordinate of x-axis andy coordinate of y-axis can be determined.

Referring to FIG. 8A, a method for locating a touch point on the liquidcrystal module of one embodiment of the present disclosure includessteps of:

step 31, inputting driving electrical signals with the same pulsewaveforms or other waveforms from the driving circuit 17 to each secondelectrode 108 in sequence or simultaneously;

step 32, reading out the sensed electronic signal of each firstelectrode 106 by the sensing circuit 18; and

step 33, determining the location/position of the touch point by thecontroller 19 according to the sensed electronic signals.

For the touch point locating system of the LCD module shown in FIG. 7B,the second transparent conductive layer 104 is used as the bottomconductive film, and the first transparent conductive layer 102 is usedas the top conductive film, such that the driving electronic signals areinput to the bottom conductive film and the sensed electronic signalsare generated from the top conductive film.

Referring to FIG. 8B, the step 33 of determining the location/positionof the touch point includes steps 331A and 332A. In step 331A, thecoordinate of the touch point along y-axis is obtained through locatingthe coordinate or position of the first electrodes 106 (e.g., the firstelectrode 106 designated as “13” in FIG. 7B) sensing the electronicsignal with a maximum variation of waveform amplitude by comparingbefore touching with during touching. In step 332A, the coordinate ofthe touch point along the x-axis is obtained through locating thecoordinate or position of the second electrodes 108 corresponding to themaximum variation of the waveform amplitude by comparing the signalwaveforms of the sensed electronic signals of the first electrodes 106before touching with during touching.

When the waveform of the electronic signal received by each secondelectrode 108 is the pulse waveform, the waveform of the electronicsignals sensed by each first electrode 106 are shown in FIG. 9A if thereis only one touch point. As shown in FIG. 9A, the sections of thewaveform from left to right are generated from the pulse signals inputby the ten second electrodes 108 designated from “3” to “48.”

Moreover, the waveform or amplitude of the sensed electronic signalresulting from the pulse signal input by the second electrodes 108 whichis the closest to the first electrodes 106 designated as “48” ismaximum. FIG. 9B shows an enlarged view of waveform 20A of an electronicsignal sensed by the first electrodes 106 corresponding to a pulsesignal input by a second electrodes 108 when no touch point is presenton the touch panel.

FIG. 9C shows an enlarged view of waveform 21A of an electronic signalsensed by the first electrode 106 such as the first electrode designatedas “13” corresponding to a pulse signal input by a second electrode 108when a touch point is present on the LCD module compared with thewaveform in FIG. 9B. Apparently, as shown in FIG. 9C, a maximumvariation between waveform 21A of the sensed electronic signal sensed bythe first electrode 106 designated as “13” after touching and waveform20A of the sensed electronic signal sensed by the same electrode beforetouching is present when a stylus or a finger touch the touch point onthe surface of the liquid crystal module shown in FIG. 7B.

FIG. 10A shows a touch point locating system of the liquid crystalmodule of another embodiment of the present disclosure. Each firstelectrode 106 connects to an electronic signal input circuit or adriving circuit 17 via a conductive line. The driving circuit 17 inputselectronic signals with the same pulse waveform or other waveforms toeach first electrode 106 in sequence or simultaneously. Each secondelectrode 108 connects to an electronic signal readout circuit or asensing circuit 18 via a conductive line to read out sensed electronicsignals of each second electrode 108. The first electrode 106 is used asthe driving electronic signal pad, while the second electrode 108 isused as the sensing electronic signal pad. The driving circuit 17 andthe sensing circuit 18 are controlled by a controller 19.

Referring to FIG. 10B, FIG. 10B shows a schematic view of thecombination of the first transparent conductive layer 102 and the secondtransparent conductive layer 104. In FIG. 10A and FIG. 10B, ten secondelectrodes 108 are shown and designated as from “3” to “48,” andthirteen first electrodes 106 are shown and designated from “3” to “63.”When the stylus or the finger touches the LCD module, through the touchpoint locating system, the capacitance values C generate sensedelectronic signals with specific features on the second electrodes 108so as to determine the coordinate of the touch point such as xcoordinate of x-axis and y coordinate of y-axis.

Referring to FIG. 11, a flow chart of a method for locating a touchpoint on the LCD module of one embodiment of the present disclosureincluding steps of:

331B, obtaining the coordinate of the touch point along the seconddirection or y-axis or the longitudinal axis through locating thecoordinate or position of the first electrode 106 corresponding to aminimum amplitude of signal waveform of the sensed electronic signalsresulting from touching; and

332B, obtaining the coordinate of the touch point along the firstdirection or x-axis or the transverse axis.

When the waveform of the electronic signal received by each firstelectrode 106 is the pulse waveform, the waveform of the sensedelectronic signal sensed by each second electrode 108 is shown in FIG.12A if there is only one touch point. As shown in FIG. 12A, the sectionsof the waveform from left to right are generated from the pulse signalsinput by the thirteen first electrode 106 designated from “3” to “63.”

Moreover, in one embodiment, the waveform or amplitude of the sensedelectronic signal resulting from the pulse signal input by the firstelectrode 106 which is the closest to the second electrode 108designated as “63” is maximum. FIG. 12B shows an enlarged view ofwaveform 20B of an electronic signal sensed by the second electrode 108corresponding to a pulse signal input by the first electrode 106 when notouch point is present on the liquid crystal module. FIG. 12C shows anenlarged view of waveform 21B of an electronic signal sensed by thesecond electrode 108 such as the second electrode 108 designated as “13”corresponding to a pulse signal input by the first electrode 106 when atouch point is present on the LCD module.

As shown in FIG. 12C, a maximum variation between waveform 21B of thesensed electronic signal sensed by the second electrode 108 designatedas “13” during touching and the waveform 20B of the electronic signalsensed by the same electrode before touching is present when a stylus ora finger touch the touch point on the surface of the touch panel shownin FIG. 10B. However, since the variation between the waveform 21B ofthe electronic signal during touching and the waveform 20B of theelectronic signal before touching is susceptible to RC delay and is notprecise, the detection or determination of the coordinate of the touchpoint along the first direction or x-axis or the transverse axis can notsolely rely on the variation between the waveform 21B and the waveform20B. Referring to FIG. 12A, the coordinate of the touch point along thesecond direction or y-axis or the longitudinal axis is obtained throughcomparing the signal waveforms of the sensed electronic signals read outby the second electrodes 108 to locate the coordinate or position of thefirst electrode 106 designated as 13 which inputs the electronic signalcausing the minimum amplitude of signal waveform.

The coordinate of the touch point along the second direction or y-axisor the longitudinal axis according to step 331B is obtained throughlocating the coordinate or position of the electrode corresponding tothe minimum amplitude of signal waveform of the sensed electronicsignals by comparing before touching with after touching. The coordinateof the touch point along the first direction or x-axis or the transverseaxis according to step 332B is obtained through locating the coordinateor position of the pad such as the second electrode 108 designated as“13” corresponding to a maximum variation of signal waveform of thesensed electronic signals by comparing the signal waveforms of thesensed electronic signals before touching with after touching.

However, since the variations of waveforms of electronic signals bycomparing before touching with during touching sensed by adjacent secondelectrodes 108 resulting from the input pulse signal by the sameelectrode such as the first electrode 106 designated as 13 are similar,error of the detection or determination of the coordinate of the touchpoint along the first direction or x-axis or the transverse axis isusually present.

FIG. 13A shows another embodiment of step 33 of the method for locatinga touch point on the touch panel. In this embodiment, the step 331C ofdetermining the coordinate of the touch point along the second directionor y-axis or the longitudinal axis is similar to the step 331B. Thecoordinate of the touch point along the second direction or y-axis orthe longitudinal axis is obtained through locating the coordinate orposition of the pad such as the first electrode 106 designated as “13.”Then in step 332C, a plurality of points is selected along the firstdirection or x-axis or the transverse axis corresponding to thecoordinate of the second direction or y-axis or the longitudinal axis.As shown in FIG. 13B, the x-axis coordinates of these points are thex-axis coordinates of the second electrodes 108 designated as 3, 8, 13,28 and 43. Next, in step 333C, the differences of the sensed electronicsignals of the second electrodes 108 of the points before touching withduring touching corresponding to the coordinate of the first electrode106 respectively are calculated and stored, and the unit of thedifferences of the sensed electronic signals is millivolt. In step 334C,the x-axis coordinate of the unknown touch point is obtained by thedifferences of the sensed electronic signals stored in step 333C and thedifference of the sensed electronic signal of the unknown touch pointcalculated by comparing before touching with after touching.

A transparent protective film (not shown) can be further located on theupper surface of the first transparent conductive layer 102. Thematerial of the transparent protective film can be silicon nitride,silicon dioxide, BCB, polyester, acrylic resin, PET, or any combinationthereof. The transparent protective film can also be a plastic filmtreated with surface hardening treatment. The transparent protectivefilm can reduce glare or reflection. In one embodiment, the material ofthe transparent protective film is PET.

As described above, the LCD module shares the upper polarizing layerwith the above described polarizer. Thus, the LCD module 20 can be thin,simply structured, and low cost.

It is to be understood that the described embodiments are intended toillustrate rather than limit the disclosure. Any elements described inaccordance with any embodiments is understood that they can be used inaddition or substituted in other embodiments. Embodiments can also beused together. Variations may be made to the embodiments withoutdeparting from the spirit of the disclosure. The disclosure illustratesbut does not restrict the scope of the disclosure.

What is claimed is:
 1. A liquid crystal display module comprising: aliquid crystal module comprising an upper substrate, an upper electrodelayer, a first alignment layer, a liquid crystal layer, a secondalignment layer, a thin film transistor panel, and a lower polarizinglayer stacked in that order; and a polarizer located on the uppersubstrate, having touch sensing capability, the polarizer comprising: anupper polarizing layer located on the upper substrate, having a firstsurface and a second surface opposite to the first surface, wherein thesecond surface is adjacent to the upper substrate; a first transparentconductive layer located on the first surface of the upper polarizinglayer, the first transparent conductive layer being an anisotropicimpedance layer having a relatively low impedance direction defined as asecond direction; a second transparent conductive layer located on thesecond surface of the upper polarizing layer, the second transparentconductive layer being an anisotropic impedance layer having arelatively low impedance direction defined as a first direction; aplurality of first electrodes being spaced from each other and arrangedin a row along the first direction and electrically connected with thefirst transparent conductive layer; and a plurality of second electrodesbeing spaced with each other and arranged in a row along the seconddirection and electrically connected with the second transparentconductive layer.
 2. The liquid crystal display module of claim 1,wherein the first transparent conductive layer comprises a plurality ofcarbon nanotubes substantially aligned along the second direction. 3.The liquid crystal display module of claim 1, wherein the secondtransparent conductive layer comprises a plurality of carbon nanotubessubstantially aligned along the first direction.
 4. The liquid crystaldisplay module of claim 1, wherein a first polarizing direction of theupper polarizing layer is parallel with the second direction.
 5. Theliquid crystal display module of claim 2, wherein a second polarizingdirection of the lower polarizing layer is perpendicular with the firstpolarizing direction, the upper polarizing layer and the lowerpolarizing layer are acted together to control the light extractionintensity of the liquid crystal display module.
 6. The liquid crystaldisplay module of claim 1, wherein the first direction is substantiallyperpendicular to the second direction.
 7. The liquid crystal displaymodule of claim 1, wherein the first transparent conductive layercomprises a first carbon nanotube film, and the second transparentconductive layer comprises a second carbon nanotube film.
 8. The liquidcrystal display module of claim 7, wherein each of the first and carbonnanotube films is a free-standing structure.
 9. The liquid crystaldisplay module of claim 7, wherein the first carbon nanotube filmcomprises a plurality of carbon nanotubes substantially aligned alongthe second direction, and the second carbon nanotube film comprises aplurality of carbon nanotubes substantially aligned along the firstdirection.
 10. The liquid crystal display module of claim 9, wherein anend of one carbon nanotube is joined to another end of an adjacentcarbon nanotube arranged substantially along the same direction by Vander Waals attractive force in the first carbon nanotube film.
 11. Theliquid crystal display module of claim 9, wherein an end of one carbonnanotube is joined to another end of an adjacent carbon nanotubearranged substantially along the same direction by Van der Waalsattractive force in the second carbon nanotube film.
 12. The liquidcrystal display module of claim 1, wherein the first transparentconductive layer comprises a plurality of first carbon nanotube filmsstacked with each other, and the second transparent conductive layercomprises a plurality of second carbon nanotube films stacked with eachother.
 13. The liquid crystal display module of claim 1, wherein each ofthe first transparent conductive layer and the second transparentconductive layer is a carbon nanotube composite film, and the carbonnanotube composite film comprises a carbon nanotube film and polymermaterials infiltrating the carbon nanotube film.
 14. The liquid crystaldisplay module of claim 1, wherein the first transparent conductivelayer and the second transparent conductive layer is insulated by theupper polarizing layer.
 15. A liquid crystal display module comprising:an upper polarizing layer and a lower polarizing layer, wherein theupper polarizing layer comprises: a first transparent conductive layerlocated on a first surface of the upper polarizing layer; a plurality offirst electrodes being spaced from each other and arranged in a rowalong a first direction and electrically connected with the firsttransparent conductive layer; a second transparent conductive layerlocated on a second surface of the upper polarizing layer; and aplurality of second electrodes being spaced with each other and arrangedin a row along a second direction and electrically connected with thesecond transparent conductive layer; wherein the first transparentconductive layer comprises a plurality of carbon nanotubes substantiallyaligned along the second direction, and the second transparentconductive layer comprises a plurality of carbon nanotubes substantiallyaligned along the first direction, and the liquid crystal display modulesenses touching point through the first transparent conductive layer andthe second transparent conductive layer.